9to5 Mac: OpenAI unveils GPT‑5.4‑Cyber, an AI model for defensive cybersecurity. “OpenAI has announced a new AI model called GPT-5.4-Cyber. Similar to Anthropic’s Claude Mythos, this new ‘cyber-permissive’ variant of its GPT-5.4 is built for defensive cybersecurity and not public use.”

https://rbfirehose.com/2026/04/15/9to5-mac-openai-unveils-gpt-5-4-cyber-an-ai-model-for-defensive-cybersecurity/